The Performance of Visual Perceptual Tasks in Patients with Schizotypal Personality Disorder

Background The most significant features for clinical diagnosis of schizotypal personality disorder (SPD) are cognitive-perceptual and disorganized symptoms. Experimental study of visual perceptual processes is important to elucidate the psychological mechanisms of cognitive-perceptual impairment in SPD. Objective To research the performance of visual perceptual tasks in SPD. Design Series I and II presented the subjects with visual perceptual tasks with different types of instructions (vague, verbal, or visual perceptual cues). The Wechsler Adult Intelligence Scale (WAIS-R) was also administered. The participants were 39 SPD patients, 36 obsessive-compulsive personality disorder (OCPD) patients (F.21.8, F.60.5 in ICD-10, respectively), and 102 healthy controls. Results SPD patients had a significantly lower number of correct answers in conditions of vague instruction and verbal cues in Series I of a visual-perceptual task in comparison with healthy subjects (p < 0.01). With visual perceptual cues in Series II, patients with SPD had the same number of correct answers as controls, whereas OCPD patients had the same number of correct answers as controls with verbal cues in Series I. SPD patients had significantly lower scores in most verbal and nonverbal WAIS-R subtests in comparison with controls. SPD patients differed from OCPD patients in that they had lower scores in the “Information” (p < 0.05) and “Comprehension” (p < 0.05) subtests. Conclusion With visual-perceptual cues, SPD patients were able to achieve normative results in the performance of visual-perceptual tasks, whereas patients with OCPD demonstrated lower productivity. In SPD patients, the basic impairments were associated with difficulties in inhibition of peculiar responses, stability of a subjective manner of performance and inability to revise it, low orientation to the model, and slipping into subjective associations with the stimuli.


Introduction
Psychiatric research on cognitive de cits in schizophrenia and in non-psychotic disorders within the schizophrenia spectrum is considered to be a promising approach for understanding mental dysfunction (Carruthers, Van Rheenen, Gurvich, Sumner, & Rossell, 2019;Rosell, Futterman, McMaster, & Siever, 2014). Schizotypal personality disorder (SPD) shares many biological features with schizophrenia and represents an intermediate schizophrenia-spectrum phenotype. is makes it possible to study mental disorders that do not reach the level of psychosis, to better understand the genetics, pathogenesis, and cognitive symptoms related to psychotic illnesses. At the same time, clinicians and researchers are uncertain about the boundaries on the continuum of personality pathology and psychotic pathology in SPD (Anderson & Sellbom, 2018;Smulevich, Romanov, Mukhorina, & Atadzhikova, 2017). ere are di erent mechanisms and factors that could lead to a transition from constitutional traits to susceptibility to the development of psychotic disorders: neuroanatomical peculiarities (Dickey et al., 2005;Dickey, McCarley, & Shenton, 2002;Liu et al., 2016), genetic factors (Zouraraki, Karamaouna, Karagiannopoulou, & Giakoumaki, 2017), psycho-physiological mechanisms (Ahn, Lustenberger, Jarskog, & Fröhlich, 2020;Hazlett et al., 2015;Rabella et al., 2016), etc.
Cognitive dysfunction is an essential line of modern clinical and psychological research into schizophrenia-spectrum disorders as one of the levels of the disease (Rodriguez et al., 2019;Siddi, Petretto, & Preti, 2017). Moreover, cognitive impairment in SPD is considered a prognostic indicator for the development of schizophrenia. For instance, the severity of impairment of visual perceptual processes is associated with earlier onset of the disease, the development of delusions and hallucinations, bizarre behavior, depressive symptoms, and a low level of social functioning in childhood and adolescence. In addition, a number of disturbances of the visual-perceptual processes (altered perception of one's face, body, the faces of other people, pseudo-movement, reversions, etc.) are stable and don't depend on the duration of the disease or the type of pharmacotherapy (Keane, Cruz, Paterno, & Silverstein, 2018).
Clinicians suggest that the most signi cant clinical diagnostic criteria for SPD are cognitive-perceptual (magical ideation, unusual perceptual experiences) and bizarreness, disorganized criteria (for example, eccentric behavior and speech, inappropriate, restricted a ect) (Zouraraki et al., 2017). A distinctive characteristic of cognitive-perceptual processes in SPD is their multidimensionality, not only dysfunctional manifestations, but also compensatory strategies. Psychological studies report that, on the one hand, cognitive and perceptual de cits in SPD facilitate an altered state of creativity and immersion into unusual perceptual experience; on the other, cognitive and perceptual peculiarities are an adequate way to compensate for the schizotypal maladaptation (Kallai et al., 2019). Recent studies also report the absence of manifestations of speech disorders in the aspect of originality (increasing the number of original answers), and semantic exibility in subjects with high schizotypal traits (Rodríguez-Ferreiro & Aguilera, 2019).
Psychological studies on visual perceptual processes in SPD focus on several different aspects. e neuropsychological approach describes dysfunction of spatial working memory (Smith & Lenzenweger, 2013), executive functions, information processing (Giakoumaki, 2012), processing speed (McClure, Harvey, Bowie, Iacoviello, & Siever, 2013), and attention (Carrión et al., 2011;Dickey et al., 2005). e factors determining disturbances of visual perceptual processes, speech, and thinking in SPD include increased stress and uncertainty of visual perceptual stimuli (Silverstein & Palumbo, 1995). In these conditions, patients with SPD demonstrated diminished accuracy of visual spatial memory (Smith & Lenzenweger, 2013). Disorganization of speech is reported while patients view both pleasant and stressful photographs (Minor & Cohen, 2010). e role of negative a ect (general psychological distress) in the occurrence of cognitive impairment in individuals with high schizotypy scores has also been discussed (Carrigan & Barkus, 2017).
Experimental studies of perception in patients with SPD have shown intact early visual perceptual processes and heightened mental imagery (Maróthi & Kéri, 2018), which probably contribute to perceptual aberration in SPD. One of the psychological mechanisms of unusual body experience (self-face perception abnormalities, loss of self-other boundaries) in schizophrenia spectrum disorders was demonstrated by using the Strange-Face-in-the Mirror illusion and Mirror-Gazing test (Bortolon et al., 2017;Caputo, 2010). e particular interest of modern studies of visual perceptual processes in schizophrenia spectrum disorders focuses on sensitivity to changes in target shape (for instance, target detection in symmetrical patterns and noise, congural superiority e ect, global-local divided attention task, performance on closedcontour tasks). ese studies indicate a speci c di culty with the perceptual organization of stimuli and heterogeneity of cognitive perceptual functioning in patients with schizophrenia and SPD (Panton, Badcock, & Badcock, 2016).
Social cognition is a signi cant facet of visual perceptual processing. Patients with SPD were characterized by empathic dysfunction with regard to others' negative feelings, which was associated with lower indices of social support (Ripoll et al., 2013). It is important to note the inconsistency of social cognition impairment in schizophrenia spectrum disorders. Respondents with high schizotypal traits displayed a contradiction between low cognitive empathy (ability to shi from the rstperson perspective to third-person perspective and back) and high a ective empathy (perceptual accuracy for negative cues) (Kallai et al., 2019;Lindeman, Svedholm-Häkkinen, & Lipsanen, 2015). Studies of the eory of Mind (ToM) in patients with SPD also demonstrate inconsistent ndings. While some studies showed ToM impairment in una ected relatives of schizophrenia patients (Bora & Pantelis, 2013), studies of individuals with psychometrically de ned schizotypy (Morrison, Brown, & Cohen, 2013), studies of individuals with elevated positive schizotypy scores (P um, Gooding, & White, 2013), and other studies found no signi cant di erences between respondents with schizotypal-schizoid personality disorders and controls in any of the ToM measures (Booules-Katri, Pedreño, Navarro, Pamias, & Obiols, 2019). e cultural-historical approach discusses the systemic structure of mental activity in schizotypal disorders, and the signi cant role of culture in accepting cognitive-perceptual symptoms of SPD as normative experiences (Fonseca-Pedrero et al., 2018). is approach also discusses the relations of personal components (low ethnic identity, low self-concept clarity) and cognitive components (aberrant salience) of mental activity (Cicero & Cohn, 2018). A speci c relationship was established in patients between a ective components ("emotional investment in relationships", "affective tone of relationships", empathy) and cognitive components ("сomplexity of representations", "understanding of social causality") of mentalization (Sokolova & Аndreyuk, 2018;Sokolova, Andreyuk, & Ryzhov, 2018), which emphasizes the importance of interpersonal context for understanding impairment of cognition in SPD. Various studies point out the unique role of stressful events in social relations (college enrollment, adaptation to a new social environment, external requirements, etc.) for the manifestation of symptoms of SPD (Geng et al., 2013;Quide et al., 2018). erefore, SPD is characterized by destabilization of mental activity in situations of social interaction (Herpertz & Bertsch, 2014), which is a common pattern in personality disorders. Patients with di erent types of personality disorders display in social situations disturbances of emotional regulation and control, and of executive functions; less ambiguity tolerance, loss of internal consistency and sense of selfcoherence (Gawda, Bernacka & Gawda, 2016;Giakoumaki, 2012;Osma, García-Palacios, Botella, & Barrad, 2014).
us, the investigation of visual perceptual functions in SPD requires the development of a particular methodological approach that explores the processes of mental activity in an expanded form. is approach is based on the close relationship between cognitive performance, and emotional and personality features. It includes methods that allow the researcher to vary the emotional intensity of stimuli, increase the degree of uncertainty, change instructions for tasks, and use di erent manners of stimulus presentation. Such an organization of an experiment is more sensitive and informative with regard to the structure of mental activity and the speci c characteristics of executive functions of patients with SPD. Based on the principle of cognitivea ective unity, this approach proved its e ectiveness in the investigation of hysterical personality disorder (Tkhostov & Vinogradova, 2013). e study of interdependence, di erent aspects of cognitive performance, emotional and personality features, represents an integrative approach to the interpretation of experimental data. is methodology allows us to overcome limitations of the description of cognitive impairment in personality disorder at the level of separate phenomena (Du & Kinderman, 2006) and provides a complete approach at the level of factor constellations (primary and secondary disturbances, compensatory mechanisms) (Chepeliuk & Vinogradova, 2018). e crucial role of the cognitive-perceptual and disorganization criteria of SPD identi ed in clinical studies, as well as the signi cance of special conditions of manifestation of cognitive disturbances (an increase of emotional stress, visual perceptual characteristics of stimuli) indicate the prospects for psychological study of strategies for solving visual perceptual tasks for better understanding of the psychological mechanisms of cognitive impairment in SPD. e inconsistency of visual perceptual productivity, and the ability to nd solutions corresponding to the norm di erentiate SPD from schizophrenia. ese peculiarities of visual perceptual processes in SPD align with the cognitive functions in personality disorders. At the same time, it is important to create conditions in which discrepancies among di erent types of severe personality disorders (for instance, in compensatory strategies, evaluative abilities, manner of performance) could be revealed. In our experimental study, we elaborated the conditions of di erent degrees of uncertainty, social regulation of answers, and complexity of stimuli to detect which is more sensitive in SPD patients. We have proposed that inconsistency of cognitive functioning productivity in SPD is manifested in steady alteration of conditions and the necessity to nd new ways to adapt. ese manifestations are di erentiated from those in other severe personality disorders (such as obsessive-compulsive personality disorder).
is study aimed to research the performance of visual perceptual tasks in patients with SPD, their ability to create and use compensatory strategies, conditions of normative performance and manifestation of impairments, and their severity.

Participants
e clinical groups comprised 39 patients with SPD (F21.8 in ICD-10) aged 18-55 (experimental group) and 36 patients with obsessive-compulsive personality disorder aged 18-56 (F60.5 in ICD-10, OCPD). e clinical comparison group (OCPD) is more severe than other types of personality disorders. is allows for comparability of results of cognitive tests in patients with SPD and OCPD, to elucidate similarities and di erences in psychological mechanisms of performance of visual perceptual tasks in SPD and other personality disorders. e control group consisted of 102 healthy individuals between the ages of 18 and 54. Patients were recruited from mental health clinics in Moscow (Kannabikh State Psychiatric Hospital and International Institute of Psychosomatic Health). ey were consulted by psychiatrists and signed an informed consent agreement. Patients with personality disorders and normal controls had an equivalent educational level, except in the group of patients with OCPD, who generally had higher education (p = 0.02) ( Table 1). All patients were examined before the treatment.  (Witkin, 1950) were used as stimuli. In Series I, complex gures were covered by eight simple gures and the subject had to decide whether the complex gure contains the simple one (for all 96 trials), without feedback from the experimenter. In Series II, each trial showed two complex gures simultaneously, to increase the visual perceptual load (for all 96 trials).
ree types of instructions were used. e rst one was vague ( "Do you think this gure is in a complex one?" ) and was presented a er the rst simple gure had been shown alongside the rst complex gure in Series I. e second instruction provided verbal clues about the criteria for correct answers: "Every simple gure is not necessarily embedded within every complex one, but if you nd a simple gure, it should be the same as the one in the model". is verbal clue was presented before a demonstration of the second complex gure in Series I. e third instruction involved visual perceptual cues in Series II, when one of the two simultaneously presented complex gures could be considered as a corrector for the answers. us, the procedure provides the opportunity to moderate uncertainty of stimuli and experimental conditions. e analysis of performance of visual perceptual tasks included the number of correct answers in the di erent types of instructions.
To analyze di erent aspects of the cognitive functions of patients with SPD, the study included the WAIS-R test (Wechsler Adult Intelligence Scale, revised form), with six verbal and ve performance subtests (Filimonenko & Timofeev, 2006).
Statistical signi cance was ascertained by Student's t-test for comparing independent groups, the Spearman rank correlation coe cient, a two-way 3×3 factorial analysis of variance, and Fisher's exact test to compare categorical variables.

Performance of Series I and Series II
Visual Perceptual Tasks in Patients with Schizotypal Personality Disorder, Healthy Subjects, and Patients with Obsessive-Compulsive Personality Disorder. Table 2 shows that the signi cance values of group and type of instruction are equal, p = .096, so there is no interaction e ect by group and type of instruction of visual perceptual tasks on the number of right answers in Series I and II. ANOVA showed a signi cant e ect of group and a signi cant e ect of type of instruction on the number of right answers in Series I and II. Figure 1 shows the values of the correct answers for the di erent types of instructions. e data shows that all subjects had the smallest number of answers when the key gure was presented with "vague" instructions. However, the healthy individuals had signi cantly more correct answers with "vague" instructions compared to the patients with personality disorders ( Table 3). Patients with SPD had signi cantly fewer correct answers with verbal cues in comparison with the healthy subjects (Table 3). OCPD patients had intermediate outcomes with verbal cues, with more right answers than SPD patients and less than the healthy controls, without signi cant di erences with either the SPD patients or healthy subjects (Figure 1). is result indicates the possibility of increasing the productivity of performance of visual perceptual tasks by patients with OCPD at the level of standard indicators, when the degree of uncertainty of the stimulus was reduced.
In Series II, with visual perceptual cues, there was an equal percentage of healthy subjects who found the key gures and of those who could not. e same was observed in patients with SPD, with slightly more patients who found the key gures in the pair of complex gures ( Table 3). SPD patients had no signi cant di erences in the number of correct answers in comparison with the controls (Figure 1). Patients with OCPD had signi cantly fewer correct answers with visual perceptual cues in comparison with healthy individuals ( Table 3). Note. ª R 2 = .137 (Adjusted R 2 = .120) Figure 1. e number of right answers with di erent types of instruction in Series I and II for visual perceptual tasks with patients with personality disorders and healthy controls

Comparison of Results of the Wechsler Adult Intelligence Scale (WAIS-R) in Patients with SPD and Healthy Subjects
To further illuminate the performance of visual perceptual tasks, nonverbal WAIS-R subtests were analyzed for patients with SPD in comparison with healthy subjects. Table 4 shows that the scores on the WAIS-R for patients with SPD were signi cantly di erent from those of healthy individuals. e patients scored signi cantly lower on nonverbal subtests such as the "Digit Symbol" (р ≤ .05), the "Picture Completion" (р ≤ .01), and the "Block Design" (р ≤ .01). Patients with SPD managed to ll in the same number of digits on the Digit Symbol subtest as the healthy subjects in the allotted time, but they displayed di erences in the quality of writing of the symbols. e patients more o en had a change in the slope or character size, an incorrect alignment of lines in the symbol, or extra lines. e lower scores in the Block Design subtest in patients with SPD was associated with di culty analyzing parts within the whole, when this was required to compare the results of their performance with an externally provided sample.
Patients with SPD had lower productivity in the Picture Completion subtest because of a tendency to focus on insigni cant, peculiar aspects of the stimuli.
An important characteristic of the cognitive processes of patients with SPD was the signi cantly lower score on WAIS-R verbal subtests. Analysis of performance of verbal tasks by patients with SPD allowed us to elucidate the general psychological mechanisms, which can also determine the impairment of visual perceptual processes in SPD.
On the Information subtest, SPD patients showed a paradoxical combination of di culty in extracting information reinforced by experience, and ease answering the most di cult questions. e lower scores in the Comprehension subtest in patients with SPD was caused by disregarding the social context, relying solely on the subjective manner of behavior in stimulus situations (egocentric position). In some cases, the answers of patients with SPD included both egocentric solutions and standard social criteria. When conveying the gurative meaning of non-frequent expressions, SPD patients tended to resort to magical meanings combined with situation-based generalizations. It should be noted that the patients could give the correct answers in tasks where they were asked to explain the gurative meaning of common proverbs and expressions, which suggests the ability of these patients to operate with conventionalized abstract meaning. Patients with SPD had lower scores on the Arithmetic subtest in comparison with healthy subjects, which can be explained by the former's inconsistent productivity in counting operations. ese patients, when faced with di culties in tasks with onephase counting, did not attempt to nd an answer. More rarely, patients with SPD expressed unwillingness to count. By contrast, the patients performed well on easy tasks on the Arithmetic subtest with two-phase counting, and obtained additional points for speed in these tasks. In the most complicated tasks of the Arithmetic subtest, patients with SPD easily substituted a correct description of the necessary actions, thereby avoiding counting operations.
Comparison of Performance on the Wechsler Adult Intelligence Scale (WAIS-R) in Patients with OCPD and Healthy Subjects Table 4 shows a signi cant di erence between the WAIS-R performance by patients with OCPD and healthy individuals only in the Digit Span verbal subtest (p ≤ .01). However, in nonverbal subtests, the results of patients with OCPD were signi cantly lower than with healthy subjects (in the Digit Symbol (p ≤ .05), in the Picture Completion (p ≤ .01) and in the Block Design (p ≤ .01) subtests). e lower scores on the Digit Span subtest were associated with a shi of patients' attention from the instruction for the task to thoughts of failure, greater doubts about one's own performance, abilities, etc. Patients with OCPD demonstrated on the Digit Symbol subtest the intention to accurately imitate the symbols speci ed by the instruction, which led to an excessive focus of attention on verifying the result. ey also corrected their mistakes, which slowed their performance. Preoccupation with details made the patients with OCPD take a long time searching for answers in the Picture Completion subtest, going beyond the time allocated to each item.
Patients with OCPD gave a detailed analysis of the parts that presented di culties when synthesizing them into a whole, were unable to revise their work method, doubted the correctness of the process, and o en canceled the correct answers, which reduced their productivity in the Block Design nonverbal subtest.
Patients with OCPD had signi cantly higher scores than patients with SPD on the Information (p ≤ .05) and Comprehension (p ≤ .05) verbal subtests. Analysis of the performance of nonverbal subtests by patients with di erent types of personality disorders revealed no signi cant di erences.
Correlations of Parameters of the Wechsler Adult Intelligence Scale and of the Visual Perceptual Tasks in Patients with Di erent Types of Personality Disorders In healthy subjects and patients with OCPD, there were no signi cant correlations between the number of right answers on the Series I and Series II visual perceptual tasks with di erent types of instructions, and their scores on WAIS subtests.
In patients with SPD there were signi cant positive correlations between the number of correct answers under the condition of visual perceptual cues, and the Sum of Performance scores (r = 0.37, p ≤ .05) and scores on the Object Assembly subtest (r = 0.49, p ≤ .01).

Discussion
e study revealed that patients with di erent types of personality disorders had similarities in their pro les of reduced e ectiveness in nonverbal tasks in comparison with standard indicators. e lack of di erences in performance of nonverbal tasks between patients with schizotypal and obsessive-compulsive personality disorders suggests that working with visual perceptual information is the most sensitive to deviations from standard indicators in patients with personality disorders.
Performance of the Series I and Series II visual perceptual tasks with vague instructions, and with verbal and visual perceptual cues, allows us to elucidate the psychological mechanisms behind di erences in cognitive impairment and compensatory strategies in personality disorders. Although in conditions of high uncertainty with vague instruction, patients with SPD and OCPD did not di er from healthy controls, the introduction of verbal cues in Series I brought to the fore the principal impairments in SPD patients (lack of social regulation, inability to change the manner of decision-making by comparing their solutions with the model), and the adaptive ability of patients with OCPD. e latter were able to develop their own e ective criteria based on the verbal cue (using the verbal cue "to be exactly like the model") in searching for the key gures embedded in the complex ones.
In the performance of Series II tasks with visual perceptual cues, the situation is the opposite. SPD patients could switch their attention to the second gure and treat it as a corrector to their own solutions, so, they had standard results, whereas patients with OCPD demonstrated a signi cant decrease in performance of visual perceptual tasks when two complex gures are presented simultaneously. ese ndings indicate the abilities of patients with SPD to nd a new way of adapting when the conditions of performance were changed and to follow it e ectively. is corresponds to the fact that patients with SPD had no discrepancies with normative indicators when working on nonverbal tasks with visually presented social context (the Picture Arrangement subtest) and concrete content (the Object Assembly subtest). is fact suggests that patients with SPD had no decrease in social regulation of activity in case of direct visual support of the social context. At the same time, patients with SPD display lower productivity in verbal tasks associated with a social context. erefore, among nonverbal tasks, the performance of tasks with abstract visual perceptual information is the most sensitive to impairments in patients with SPD. is result is consistent with the signi cant role of cognitive-perceptual criteria for diagnosis of SPD identi ed in clinical studies (Zouraraki et al., 2017). e decline in most cognitive parameters of the Wechsler Adult Intelligence Scale in patients with SPD corresponds to data from meta-analyses of cognitive impairment in schizophrenia spectrum disorder (Carruthers et al., 2019) and suggests greater severity of cognitive impairment in SPD patients in comparison with patients with OCPD.
SPD patients' inconsistent productivity in performing verbal tasks was caused by di culties in inhibiting subjectively signi cant responses when socio-deterministic formal criteria were available for making judgments; the stability of a subjective manner of performance and inability to revise it; vagueness in de nition of concepts; and slipping into subjective associations with the stimuli. OCPD patients are characterized by relatively intact ability to solve verbal tasks, as evidenced by lower scores than normative on only one of the verbal subtests.
Although patients with SPD and OCPD did not di er signi cantly in their scores on nonverbal tasks, the qualitative analysis revealed the principal di erences in the psychological mechanisms of their impairments. In SPD patients, the lower scores on nonverbal subtests were a result of low orientation toward the model, ease of subjective transformation of the targets, and impairment of the selectivity of cognitive processes. e latter is speci c for patients with schizophrenic spectrum disorders. is impairment is characterized by a tendency to rely on insigni cant, bizarre, unusual attributes of concepts (Kritskaya & Meleshko, 2015;Kritskaya, Meleshko, & Polyakov, 1991). e lower productivity on nonverbal subtests of patients with OCPD was associated with their detailed analysis of parts that present di culties in their synthesis, preoccupation with details, inability to revise their work method, and doubts about their accuracy, o en with the rejection of correct answers.
For healthy subjects and patients with OCPD, there was no association in Series I and Series II between productivity in performing visual perceptual tasks under conditions of di erent instructions, and the parameters on the intelligence scale, whereas in SPD patients, the productivity of the search for gures under condition of visual perceptual cues was associated with nonverbal subtests and the integrative performance score.

Conclusion
e patients with SPD had more severe cognitive impairment than the OCPD patients. e former had lower productivity in performance of verbal and nonverbal tasks. Patients with OCPD had di culties only in the performance of nonverbal tasks, whereas in verbal tasks they had scores corresponding to the normative.
It is important to note the speci c mechanisms of impaired cognitive functioning in SPD. e basic impairment in these patients was associated with di culties in inhibition of bizarre responses, stability of the subjective manner of performance and inability to revise it, low orientation to the model, and slipping into subjective associations with the stimuli. In OCPD it was associated with a shi of patients' attention from the instruction about the task to thoughts of failure, strengthening of doubts, and excessive focus on checking one's performance.
Varying the degree of uncertainty of the visual perceptual tasks with abstract stimuli made it possible to reveal the speci c compensatory strategies of patients with SPD, which help to increase the productivity of the performance. So, under the condition of visual perceptual cues, these patients could achieve normative results, whereas patients with OCPD demonstrated lower productivity. ese facts also suggest that the performance of visual perceptual tasks in patients with SPD is characterized by inconsistent productivity and the availability of compensatory strategies that increase the performance to normative levels.
is experimental study has some clinical implications. First, these ndings broaden the pathopsychological picture of impairments of visual perceptual processes and compensatory strategies of patients with SPD. Second, it should be useful for di erential diagnostics of severe personality disorders, SPD, and other schizophrenia-spectrum disorders. Furthermore, these results contribute to addressing complex issues of social and daily-life adaptation, occupational activity, and productivity of SPD patients.

Limitations
e current study had several limitations that should be addressed in future research. First, it might be informative to compare the results of cognitive tasks of patients with SPD and schizophrenic patients (pseudoneurotic type), to discuss speci c and general impairment of cognitive productivity in schizophrenia-spectrum disorders. Second, it would be promising to discuss the duration of clinical symptoms and their association with the change or intactness of cognitive productivity in the performance of the visual perceptual tasks in patients with SPD.

Ethics Statement
All participants were consulted by psychiatrists voluntarily and signed an informed consent before taking part in the research.

Author Contributions
Marina Vinogradova and Anastasia Chepeliuk conceived of the idea. Anastasia Chepeliuk developed the theory and performed the computations. Marina Vinogradova supervised the ndings. e authors discussed the results and contributed to the nal manuscript.